Just 26 percent of girls in northern Nigeria make it beyond primary school, according to the UN Children's Fund, and local NGOs estimate that most of those who leave do so because their families marry them off.

A British law went into effect Tuesday that allows courts to prevent someone from being forced into marriage — a move that comes as governments across Europe confront immigrant practices that sometimes clash with more liberal values.

Arwa is the youngest of three Yemeni girls who recently went to court complaining they were married against their will and asking for divorce - an astonishing display of defiance that has prompted the government to review its law on early marriage.

"Police raided a wedding between a 7-year-old boy and a 5-year-old girl in Pakistan's largest city, arresting the Muslim cleric officiating at the ceremony and the children's parents, a senior officer said Friday."